I picked this up at a local farmers' market for $15, thinking it was an older model. I did some research and found that this was the "J" was sold during the Roaring 20's, so it's not the original Comptometer from the late 19th century. The first units had a wooden case. Oh well, still interesting looking. The woman who sold it to me said they have the missing key and will mail it to me. Someone else at the table asked me, "Looks like some kind of peg game or something"